Impact of the COVID-19 pandemic on thoracic surgery volume in Japan: an analysis of the National Clinical Database

Introduction: The COVID-19 pandemic has disrupted elective surgeries worldwide. This study evaluated the impact of the pandemic on thoracic surgery volumes in Japan and investigated real-world triage practices by thoracic surgeons. Methods: Using Japan’s National Clinical Database, we analyzed both annual and quarterly trends in surgical procedures and patient characteristics of lung and thymic tumors from 2019 to 2023. Results: Compared to 2019, surgeries for primary lung cancer, thymic tumors, and spontaneous pneumothorax declined in 2020, with the most pronounced decreases occurring in Q2 during Japan’s first state of emergency. Specifically, the numbers declined by 8.7%, 9.7%, and 27.1%, respectively. The greatest decline in pathological (p-) stage 0–IA1 lung cancer cases occurred in Q2 2020 (− 22% vs. Q2 2019), while reductions in more advanced stages during Q2 remained below 10%, with peak decreases observed in Q3. By 2023, the number of p-Stage II–IV cases had decreased, while the number of IA1–IB cases had increased. Thymoma and thymic cysts declined in Q2 2020 (− 4.4%, − 35.1%, respectively), but thymic cancer remained stable. Notably, thymic tumor size showed no temporal change throughout the study period. Discussion: Despite strategic triage by thoracic surgeons during the initial phase of the pandemic, the overall disease profile of thoracic malignancies remained largely unaffected by treatment delays through 2023 in Japan. (200 words).